This invention refers to a cutting device for a plotter for carrying out the cutting of the paper band at the end of a plotting cycle.
The application of this invention is foreseen for plotters which have a continuous paper band consisting of a roll of paper incorporated on the plotter, so that at the end of each plotting cycle, a paper band length has to be cut which comprises the graphic representation drawn by the plotter.
According to the present state of the art, a number of devices have been disclosed for cutting the paper band in plotters and printers.
To obtain high quality cuts of the paper band, sliding carriages are usually provided to cut the paper. Such cutter carriages are independent of the plotting carriage or printing device, having independent motors and transmission systems to produce the displacement of the cutting carriage along straight guides in order to carry out the cutting of the paper band usually by means of a rotating cutter.
Thus, as an example, German Patent DE3119998 discloses a device for the cutting of a continuous paper band comprising a carriage which may slide along specific guides and which has a motor to operate a toothed belt which is connected to a wheel incorporated on the shaft carrying the rotating cutter. This prior disclosure shows as well a couple of angle shaped plates for the guidance of the continuous paper band in the vicinity of the cutter carriage.
In other cases, straight cutters are provided to act on the whole width of the continuous paper band, practically with a single stroke.
An example of this technique is disclosed in U.S. Pat. No. 4,617,577, which shows a device for the cutting of paper sheets by means of a rotating cutter which has a swiveling movement from a rest position up to a cutting position, coming back to the starting position after each cutting cycle. In this case, there is no movable carriage as the cutting is carried out in only one stroke on the whole width of the paper sheet.
This system does not permit to obtain high quality cuts on the paper band as the cutting action is simply carried out by compression between the swiveling cutter and the fixed cutter. Besides, the system is not appropriate for great paper band widths.